• Childhood Kidney Diseases
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• v.20 no.2
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• pp.74-78
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• 2016

Purpose: Early diagnosis and treatment of urinary tract infection have been emphasized to prevent renal scarring. If untreated, acute pyelonephritis could cause renal injury, which leads to renal scarring, hypertension, proteinuria, and chronic renal failure. The purpose of this study was to assess risk factors of renal scarring after treatment of acute pyelonephritis (APN). Methods: The medical records of 59 patients admitted at Daegu Fatima Hospital because of APN between March 2008 and April 2015 whose renal cortical defects were confirmed by using initial technetium-99m dimercaptosuccinic acid (DMSA) scans were reviewed retrospectively. We divided 59 patients into 2 groups according to the presence of renal scar and assessed risk factors of renal scar, including sex, age at diagnosis, feeding method, hydronephrosis, bacterial species, vesicoureteral reflux, and vesicoureteral reflux grade. Results: Of 59 patients (41%), 24 showed renal scar on follow-up DMSA scan. No significant differences in sex, hydronephrosis, bacterial species, and fever duration were found between the renal-scarred and non-scarred groups. As for age at diagnosis, age of >12 months had 5.8 times higher incidence rate of renal scarring. Vesicoureteral reflux (VUR) affected renal scar formation. VUR grade III or IV had 14.7 times greater influence on renal scar formation than VUR grade I or II. Conclusion: Our data suggest that the presence of VUR and its grade and age at diagnosis are risk factors of renal scar on follow-up DMSA scan after APN.

• Clinical and Experimental Pediatrics
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• v.55 no.10
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• pp.367-370
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• 2012

Urinary tract infection (UTI) is a common bacterial illness in children. Acute pyelonephritis in children may lead to renal scarring with the risk of later hypertension, preeclampsia during pregnancy, proteinuria, and renal insufficiency. Until now, vesicoureteral reflux (VUR) has been considered the most important risk factor for post-UTI renal scar formation in children. VUR predisposes children with UTI to pyelonephritis, and both are associated with renal scarring. However, reflux nephropathy is not always acquired; rather, it reflects reflux-associated congenital dysplastic kidneys. The viewpoint that chronic kidney disease results from renal maldevelopment-associated VUR has led to questioning the utility of any regimen directed at identifying or treating VUR. Despite the recognition that underlying renal anomalies may be the cause of renal scarring that was previously attributed to infection, the prevention of renal scarring remains the goal of all therapies for childhood UTI. Therefore, children at high risk of renal scar formation after UTI should be treated and investigated until a large clinical study and basic research give us more information.

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.43-50
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• 2001

Purpose : The urinary tract infection associated with vesicoureteral reflux(VUR) in children may result in serious complications such as renal scarring, hypertension, proteinuria and end stage renal disease. The purpose of this study was to evaluate the factors affecting renal scar such as age, gender, grade of VUR, and ACE gene polymorphism, and body growth in the patients with and those without renal scar associated with VUR Methods : During the period from January 1994 to July 2000, We had 93 children with urinary tract infection associated with VUR who were admitted to the Department of pediatrics of Chonbuk National University Hospital. The patients were divided into two groups according to follow up 99mTc-DMSA renal scan; patients with renal scar group and those with non-scar group. We analyzed and compared the factors associated with renal scarring between the two groups. Results : There were no significant difference in gender, causative organism, ACE gene polymorphism, height and weight at diagnosis between renal scar group and non-scar group. Fifty four patients were in renal scar group and forty seven of them had VUR. The age at diagnosis was significantly higher in renal scar group (2.48${\pm}$2.64yr) than in non renal scar group (1.26${\pm}$1.83yr). Especially, the infants who were less than 1 year of age with VUR developed relatively more renal scar compared with infants older than 1 tear of age. The incidence of renal scarring showed a direct correlation with the severity of VUR. Conclusion : The factors affecting renal scar formation were age at diagnosis, presence and grade of VUR, but the other factors such as gender, causative organism, ACE gene polymorphism were not associated with renal scarring. Therefore, further evaluation about uropathogenic E coli and foflow up study about body growth associated with severity of renal scar would be necessary. (J. Korean Soc Pediatr Nephrol 5 : 43- 50, 2001)

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.44-51
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• 2003

Purpose : Acute pyelonephritis in children may result in permanant renal damage which later in life may lead to hypertension and renal failure. The purpose of this study was to evaluate the factors that might be useful for predicting the development of renal scar in children with urinary tract infection(UTI). Methods : We retrospectively reviewed 442 patients with UTI who were admitted to the Department of Pediatrics of Chonbuk National University Hospital, during the period from April 1992 to March 2002. The patients were divided into two groups according to the presence of renal scar on the follow-up DMSA renal scan, and we compared the factors associated with renal scarring between the two groups. Results : There were no significant differences in sex, causative organism and acute phase reactants between the groups with and without renal scar. The age at diagnosis was significantly higher in the renal scar group compared to that without scar. Of the 60 patients with renal scar, 78% had vesicoureteral reflux(VUR), but 13% of patients without scar had VUR. Furthermore, the severity of VUR was significantly correlated with renal scar formation. 53% showed multiple cortical defects on the initial DMSA renal scan, compared to 32% in the non-scar group. In addition, 76% of patients showing multiple cortical defects on the initial DMSA renal scan with VUR had renal scar. Conclusion : The presence and grade of VUR, and findings on the initial DMSA renal scan would contribute to predict risk of renal scar formation in children with UTI.

• Childhood Kidney Diseases
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• v.10 no.2
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• pp.201-212
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• 2006

Purpose : Vesicoureteral reflux(VUR) is the major risk factor of urinary tract infection(UTI) in children and may result in serious complications such as renal scarring and chronic renal failure. The purpose of this study was to evaluate the relationship between VUR and renal scar formation, the usefulness and correlation of various imaging studies in reflux nephropathy, and the spontaneous resolution of VUR. Methods : We retrospectively reviewed 106 patients with VUR with no accompanying urogenital anomalies in the Department of Pediatrics, Bundang CHA Hospital during the period from Jan. 1996 to Mar. 2005. Ultrasonography and $^{99m}Tc$-dimercaptosuccinic acid(DMSA) scan were performed in the acute period of UTI. Voiding cystourethrography(VCUG) was performed 1 to 3 weeks after treatment with UTI. Follow-up DMSA scan was performed 4 to 6 months after treatment and a follow-up VCUG was performed every 12 months. Results : The mean age at detection of VUR was $13.8{\pm}22.2$ months and the male to female ratio was 2:1. The incidence of renal scarring showed a tendency of direct correlation between severity of VUR(P<0.001) and abnormal findings of renal ultrasonography(P<0.01). 63.2%(24 of 38 renal units) of renal parenchymal defects present in the first DMSA scan disappeared on follow-up DMSA scans. Follow-up DMSA scans detected renal scars in 7(14%) of 50 renal units with ultrasonographically normal kidneys. Meanwhile, ultrasonography did not show parenchymal defects in 7(36.8%) of 19 renal units where renal scarring was demonstrated on a follow-up DMSA scan. The spontaneous resolution rate of VUR was higher(75%) in cases with low grade(I to III) VUR(P<0.01). Conclusions : The presence and severity of VUR and abnormal findings of renal ultrasonography significantly correlated with renal scar formation. DMSA scan was useful in the diagnosis of renal defects. Meanwhile renal ultrasonography was an inadequate method for evaluating renal parenchymal damage. Therefore, follow-up DMSA scans should be performed to detect renal scars even in children with low-grade VUR and normal renal ultrasonography.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.998-1003
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• 2005

Purpose : We evaluated the occurrence of renal scarring in children with unilateral vesicoureteral reflux(VUR), and the relationships between renal scar formation and risk factors such as VUR, duration of fever, acute-phase reactant, age, and sex. Methods : We retrospectively analyzed the data of 35 children newly diagnosed with unilateral vesicoureteral reflux after urinary tract infection(UTI) in Wallace Memorial Baptist Hospital between January 1996 and December 2004. Ultrasonography, Erythrocyte sedimentation rate(ESR), and C-reactive protein(CRP) were performed initially. Voiding cystourethrography(VCUG) was performed 1 to 3 weeks after treatment with UTI. $^{99m}Tc$-dimercaptosuccinic acid(DMSA) scan was performed 4 to 6 months after treatment. Results : Scintigraphic renal damage was present in 29 percent of the refluxing and in 3 percent of the nonrefluxing kidneys(P<0.05). The severity of VUR was significantly correlated with renal scar formation(P<0.05). The duration of fever before treatmen($5.0{\pm}1.3$ vs $2.6{\pm}1.3$) and prolonged fever of over 5 days were significantly different between renal scar group and non-renal scar group(P<0.05). ESR($56.3{\pm}23.8$ vs $27.9{\pm}18.1mm/hr$, P<0.05) and CRP($12.8{\pm}7.3$ vs $3.9{\pm}3.8mg/dL$, P<0.05) at the diagnosis of UTI in the renal scar group were higher, compared to those of the non-renal scar group. There were no significant differences in age and sex between the two groups. Conclusion : The presence and grade of VUR, the duration of fever before treatment, prolonged fever over 5 days, ESR, and CRP were risk factors for renal scarring, irrespective of age and sex. Diagnosis and management of VUR, in children with UTI, is important to prevent renal scars.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.245-253
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• 2003

Puorpose: The purpose of this study was to evaluate the usefulness of $^{99m}Tc$ DMSA scintigraphy on the dignosis of a renal scar in children with urinary tract infections. Materials and Methods: Eighty three patients were included in this study, who were diagnosed as the urinary tract infection on the basis of symptom, urinalysis and urine culture. $^{99m}Tc$ DMSA scintigraphy and voiding cystoureterography were peformed within 7days before the treatment in all patients. We classified the scintigraphic findings as follow s : 1 ; a large hypoactive upper or lower pole. 2 ; a small hypoactive area. 3 ; single defect resulting in localized deformity of the outlines. 4 ; deformed outlines in a small or normal sized kidney. 5 ; multiple defects. 6 ; diffuse hypoactive kidney without regional impairment. Follow-up scintigraphy was done at least 6 months after the initial study. When the abnormality on the initial scintigraphy was not completely resolved on the follow-up scan, the lesion was defined as containing a scar. Results: One hundred and fifteen renal units of 166 units(69.3%) showed abnormal findings on the DMSA scintigraphy. 65 units(56.5%) was diagnosed as containing renal scars on follow-up scintigraphies. Incidences of renal scar among renal units showing pattern 3, 4 and 5 on the initial scan was 75%, 78% and 78%, respectively. Whereas many of renal units showing 1, 2 and 6 pattern were recovered(65%, 76%, 50%). Sensitivity, specificity and accuracy of pattern-based DMSA scintigraphic findings on the diagnosis of renal scar was 76.9%, 85.1% and 81.9%, respectively. VUR was significantly associated with the renal scar when the initial DMSA shows unrecoverable findings(pattern 3, 4, 5). Odds ratio of the renal scar in a kidney showing unrecoverable initial scintigraphic findings was 19.1. Odds ratio in a kidney with mild or moderate-to-severe VUR was 3.5 and 14.4 respectively. Conclusion: In the urinary tract infection, renal scar was significantly developed in a kidney showing unrecoverable findings on the initial DMSA scan and VUR on voiding cystoureterography.

• Childhood Kidney Diseases
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• v.1 no.1
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• pp.46-52
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• 1997

Urinary tract infection (UTI) in children has been known to be a cause of renal damage, leading to scar formation, hypertension and renal failure. And vesico-ureteral reflex (VUR), frequently accompanying UTI in young children, has been incriminated as the main factor causing scar formation. This retrospective study has been undertaken to see the relationship among UTI, VUR and renal scar formation. Study population consisted of 291 children (boy 134, girl 42) with UTI, who have been admitted to the Pediatric Department of Kyungpook University Hospital during 6 1/2 year period from January 1990 to June 1996. VUR was diagnosed by VCUG and renal scar by ultrasonogram, DMSA scan (or DMSA SPECT) and IVP. The following result were obtained. Sexual difference showed male predominance (male to female, 134:42) below 1 year of age, and female predominance (male to female, 11:35) over 5 years of age were rioted. VUR has been found in 64 children (22%) and the degree of reflux, classfied by the method proposed by 'International Reflux Study in Children', were as follows ; Grade I : 4.0%, Grade II : 3.0%, Grade III : 2.7%, Grade IV : 5.8% and Grade V : 6.2%. There was no sexual difference E.coli was the most predominant infecting agent occurring in 167 children (57%), and end-stage renal failure was diagnosed at the time of first admission in 5 children with Grade V VUR. Renal scar has been noted in 49 out of 582 kidneys (8.4%), and the incidence of scar foramation according to the degree of VUR were as follow ; Grade 0 (No reflux) : 1.2%, Grade I : 6.7%, Grade II 27.3%, Grade III 29.4%, Grade IV : 57.1%, and Grade V : 100%. In summary, present study shows that renal scar formation in UTI has close correlation with the severity of VUR occurring more frequently in severe reflux, so that early diagnosis and proper treatment of UTI and VUR is of paramount importance in preventing renal damage in children with UTI.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.193-200
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• 2005

Purpose : An atrophic renal scar(RS) is one of the underlying causes for childhood hyper tension and chronic renal failure. The risk factors for atrophic renal scar were evaluated. Methods : 41 children, who presented with first febrile urinary tract Infection at the Ewha Womans University Hospital between 1995 and 2003 and had generalized atrophic RS on $^{99m}Tc-DMSA$ renal scan, were retrospectively studied. Atrophic RS was divided into severe atrophic RS(n=14) if relative uptake on renal scan was below 10$\%$, or mild atrophic RS(n=27) if relative uptake on renal scan was between 10-35$\%$. RS was defined as congenital if the scar was detected on the first renal scan, and as acquired if the scar developed on the follow-up renal scan from acute pyelonephritis of the first renal scan. The control group was consisted of randomly selected 41 children with segmental RS. The risk factors for atrophic RS such as the generation time, VUR, gender and ACE gene polymorphism were evaluated. Results : The age distribution of atrophic RS and segmental RS did not differ significantly (P>0.05). The rate of congenital RS in atrophic RS was 61.0$\%$(25/41), which was significantly higher than 9.8$\%$(4/41) of segmental RS(P<0.01). Atrophic RS developed mote frequently in male children(M:F 68.3$\%$ 31.7$\%$) than segmental RS(M:F 41.4$\%$ .58.5$\%$)(P<0.05). Vesicoureteral reflux(VUR) was found in 92.7$\%$(38/41) of 4he atrophic RS, which was significantly higher than 53.7$\%$(22/41) of segmental RS(P<0.05). In children without VUR, the male to female ratio did not differ between atrophic RS and segmental RS(P>0.05) But in children with VUR, there was a higher proportion of males with severe atrophic RS than segmental RS($85.7\%:45.5\%$) ACE gene polymorphism did not differ between the atrophic and segmental RS groups, irrespective of the presence of VUR(P>0.05). Conclusion : Most atrophic RSs were congenital which could not be preventable postnatally and the major risk factors were VUR and the male gender. ACE gene polymorphism was not the significant risk factor for an atrophic RS. (J Korean Soc Pedialr Nephrol 2005;9:193-200)

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.70-77
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• 2008

Purpose: Urinary tract infections(UTIs) are not uncommon findings in febrile pediatric patients and approximately one third of patients with UTI may have renal scars. This research was intended to establish the relationship between duration of fever and renal scars. Methods: The medical records of 143 patients were reviewed retrospectively. Inclusion criteria were as follows: 1) fever as defined by an axillary temperature $\geq37.5^{\circ}C$, 2) accurate history of fever duration and the use of antibiotics 3) no previous history of UTI and 4) positive urine culture. We observed whether the longer fever duration could be associated with the development of initial renal defects and subsequent renal scars, increased C-reactive protein(CRP), leukocytosis and the presence of vesicoureteral reflux(VUR). Results: 1) Patients with longer fever duration after antibiotics showed more frequent initial renal defects(P=0.014). However, fever duration before antibiotic use was not associated with the development of initial renal defects(P=0.244). 2) Incidence of renal scar increased with fever duration before antibiotic use(P=0.006) and fever duration after antibiotic use(P=0.015). 3) CRP correlated with the fever duration after antibiotic use(r=0.287, P=0.003). 4) There was no relationships between fever duration and VUR(P>0.05). Conclusion: Our data suggest that fever duration before/after antibiotic use is significantly associated with the increased development of renal scars in pediatric UTI.